All posts by Michael Perry
Below are all of Michael Perry's postings, with the most recent are at the bottom of the page.
nick horrex:
It was considered carefully when the usage of channels was planned. But the main problem you have is that the weather causes signals to travel much further than normal at times of high pressure or high temperatures. As that is a well known natural phenomenon there is nothing anyone can do to prevent irt happening. All you can do is to ensure that your aerial system as as directional as possible, even if that means using a higher gain aerial and fitting attenuators, and siting it so that it does not 'see' the signal from unwanted sources. The aerial has to be very carefully aimed so that any side lobe reception does not include the unwanted signals.
I once had a customer who had a simialr problem and we had a 48 element high gain aerial fitted (they have far better rejection of unwanted signals) and we had to adjust the aim so that it received the wanted signals but not the unwanted ones.
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Colin Case:
To be able to offer any meaningful suggestion s we need you to provide a full post code. Then we will be able to see what the expected reception conditions are like at your location.
Meanwhile, please check all your aerial connections that you can safely reach. Unplug all the connections and reinsert them - corrosion/oxidation on the contacts is a well known cause of symption similar to those you describe.
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Alan:
What you describe suggests that either one element of your LNB has failed or there is a fault in the cable connecting to the non-working input. As one works if your swap the cables then it shows your box is OK.
So carefully check all the connections in the 'F' connector that is not working correctly. Note that there must be no fine wires crossing between the inner and outer conductors and that the connector must be fully and firmly screwed on to the end of the cable with the inner core protruding enough to make contact within the socket.
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Paul Cooper:
The Bluebell Hill transmitter had some engineering works done on Friday between 18.14 and 18.51, when it returned to normal service.
Did you by any chance perform a retune during that time? If so, you need to retune again.
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Mark Rigley:
There are no works listed on the Digital UK website for Emley Moor. If there were problems with the transmitter it would be expected to create many more questions but there are none.
So it woulld suggest you have a problem with your system. Please could you tell us what the signal strengths are on one of the TV's and give a full post code so we can loom up the expected reception conditions for your location.
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Mike:
To be able to give any meaningful advice we need you to provide a full poist code so we can see the expected reception conditions for your location. There are over 1100 transmitters around the UK and without any indication of where you are and what transmitter yiou are use we cannot advise.
Please also give the signal strength readings for the BBCB multiplex.
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Kathleen:
We need to know which transmitter you are using so please provide a full post code. Then we will be able to see what the signal reception conditions are like at your location and advise accordingly.
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Nick:
Reducing the voltage supplied to the amplifier is very likely to seriously affect the way it operates. The electronics is designed to operate with a specified supply voltage and if that reduces it may well not work as originally intended. Think of what happens to a radio when the batteries are going flat. Think of how a battery powered clock slows down when the battery needs replacing.
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Nick Horrex:
Mast-head amplifiers are all fixed gain and sealed against water ingress to protect the electronics. Variable gain amplifiers are not waterproofed at all as they are designed to sit close to the TV. Sadly that is not the best place for the amplifier as the downlead picks up extraneous signals/noise that you don't want and that gets amplified as well. So the best place for an amplifier is at the mast head immediately under the aerial, but a few inches away.
An old volume control does not work in the way you seem to think, so will be useless for what you describe. Likewise, a variable gain control on a signal amplifier is not something you can just put into the leads - it has associated electronics that are an essential part of a controlled gain amplifier.
Depending on the design of the amplifier, varying the supply voltage will not achieve the variable gain you seek. In many cases reducing the voltage will initially have no effect until you reduce the voltage enough - when it will stop working altogether! So no signal at all. In other cases it will have little effect but may cause the amplifier to become unstable, so pretty useless.
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Friday 17 August 2018 10:34AM
tERRY rEED:
Com7 and Com8 are temporary services from 30 main transmitters only. At some point in the future it is likely they will be turned off and probably replaced with services on more transmitters when it is viable to convert all of them to use DVB-T2 encoding, which is capable of carrying more data/channels. But that will require everyone to have equipment that can receive and decode DVB-T2 encoded signals. Current SD-only equipment cannot decode the DVB-T2 signals, on those that are Freeview HD capable can do that.